//===----------------------------------------------------------------------===//
//
// This source file is part of the Swift open source project
//
// Copyright (c) 2014-2017 Apple Inc. and the Swift project authors
// Licensed under Apache License v2.0 with Runtime Library Exception
//
// See http://swift.org/LICENSE.txt for license information
// See http://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
//
//===----------------------------------------------------------------------===//

import Basics
import PackageGraph
import PackageLoading
import PackageModel
import SourceControl
import SPMTestSupport
import XCTest

import enum TSCBasic.JSON
import protocol TSCBasic.JSONMappable
import protocol TSCBasic.JSONSerializable

import func TSCUtility.measure
import struct TSCUtility.Version

import class TSCTestSupport.XCTestCasePerf

private let v1: Version = "1.0.0"
private let v1Range: VersionSetSpecifier = .range("1.0.0" ..< "2.0.0")

class DependencyResolverRealWorldPerfTests: XCTestCasePerf {
    func testKituraPubGrub_X100() throws {
        #if !os(macOS)
        try XCTSkipIf(true, "test is only supported on macOS")
        #endif
        try runPackageTestPubGrub(name: "kitura.json", N: 100)
    }

    func testZewoPubGrub_X100() throws {
        #if !os(macOS)
        try XCTSkipIf(true, "test is only supported on macOS")
        #endif
        try runPackageTestPubGrub(name: "ZewoHTTPServer.json", N: 100)
    }

    func testPerfectPubGrub_X100() throws {
        #if !os(macOS)
        try XCTSkipIf(true, "test is only supported on macOS")
        #endif
        try runPackageTestPubGrub(name: "PerfectHTTPServer.json", N: 100)
    }

    func testSourceKittenPubGrub_X100() throws {
        #if !os(macOS)
        try XCTSkipIf(true, "test is only supported on macOS")
        #endif
        try runPackageTestPubGrub(name: "SourceKitten.json", N: 100)
    }

    func runPackageTestPubGrub(name: String, N: Int = 1) throws {
        let graph = try mockGraph(for: name)
        let provider = MockPackageContainerProvider(containers: graph.containers)

        measure {
            for _ in 0 ..< N {
                let resolver = PubGrubDependencyResolver(provider: provider, observabilityScope: ObservabilitySystem.NOOP)
                switch resolver.solve(constraints: graph.constraints) {
                case .success(let result):
                    let result: [(container: PackageReference, version: Version)] = result.compactMap {
                        guard case .version(let version) = $0.binding else {
                            XCTFail("Unexpected result")
                            return nil
                        }
                        return ($0.package, version)
                    }
                    graph.checkResult(result)
                case .failure:
                    XCTFail("Unexpected result")
                    return
                }
            }
        }
    }

    func mockGraph(for name: String) throws -> MockDependencyGraph {
        let input = AbsolutePath(#file).parentDirectory.appending("Inputs").appending(component: name)
        let jsonString: Data = try localFileSystem.readFileContents(input)
        let json = try JSON(data: jsonString)
        return MockDependencyGraph(json)
    }
}


// MARK: - JSON

public extension MockDependencyGraph {
    init(_ json: JSON) {
        guard case .dictionary(let dict) = json else { fatalError() }
        guard case .string(let name)? = dict["name"] else { fatalError() }
        guard case .array(let constraints)? = dict["constraints"] else { fatalError() }
        guard case .array(let containers)? = dict["containers"] else { fatalError() }
        guard case .dictionary(let result)? = dict["result"] else { fatalError() }

        self.init(
            name: name,
            constraints: constraints.map(PackageContainerConstraint.init(json:)),
            containers: containers.map(MockPackageContainer.init(json:)),
            result: Dictionary(uniqueKeysWithValues: try! result.map { value in
                let (container, version) = value
                guard case .string(let str) = version else { fatalError() }
                let package = PackageReference.localSourceControl(identity: .plain(container.lowercased()), path: try .init(validating: "/\(container)"))
                return (package, Version(str)!)
            })
        )
    }
}

private extension MockPackageContainer {
    convenience init(json: JSON) {
        guard case .dictionary(let dict) = json else { fatalError() }
        guard case .string(let identifier)? = dict["identifier"] else { fatalError() }
        guard case .dictionary(let versions)? = dict["versions"] else { fatalError() }

        var depByVersion: [Version: [(container: String, versionRequirement: VersionSetSpecifier)]] = [:]
        for (version, deps) in versions {
            guard case .array(let depArray) = deps else { fatalError() }
            depByVersion[Version(version)!] = depArray
                .map(PackageContainerConstraint.init(json:))
                .map { constraint in
                    switch constraint.requirement {
                    case .versionSet(let versionSet):
                        return (constraint.package.identity.description, versionSet)
                    case .unversioned:
                        fatalError()
                    case .revision:
                        fatalError()
                    }
                }
        }

        try! self.init(name: identifier, dependenciesByVersion: depByVersion)
    }
}

private extension MockPackageContainer.Constraint {
    init(json: JSON) {
        guard case .dictionary(let dict) = json else { fatalError() }
        guard case .string(let identifier)? = dict["identifier"] else { fatalError() }
        guard let requirement = dict["requirement"] else { fatalError() }
        let products: ProductFilter = try! JSON(dict).get("products")
        let ref = PackageReference.localSourceControl(identity: .plain(identifier), path: .root)
        self.init(package: ref, versionRequirement: VersionSetSpecifier(requirement), products: products)
    }
}

private extension VersionSetSpecifier {
    init(_ json: JSON) {
        switch json {
        case .string(let str):
            switch str {
            case "any": self = .any
            case "empty": self = .empty
            default: fatalError()
            }
        case .array(let arr):
            switch arr.count {
            case 1:
                guard case .string(let str) = arr[0] else { fatalError() }
                self = .exact(Version(str)!)
            case 2:
                let versions = arr.map { json -> Version in
                    guard case .string(let str) = json else { fatalError() }
                    return Version(str)!
                }
                self = .range(versions[0] ..< versions[1])
            default: fatalError()
            }
        default: fatalError()
        }
    }
}

extension ProductFilter: JSONSerializable, JSONMappable {
    public func toJSON() -> JSON {
        switch self {
        case .everything:
            return "all".toJSON()
        case .specific(let products):
            return products.sorted().toJSON()
        }
    }

    public init(json: JSON) throws {
        if let products = try? [String](json: json) {
            self = .specific(Set(products))
        } else {
            self = .everything
        }
    }
}
